Stones to Ounces Converter

A stone is exactly 14 pounds, which equals 6.35029318 kilograms, or 6,350.29318 grams. It is a body-weight unit used in the United Kingdom and Ireland, not part of the metric system.

Stones are used almost exclusively for adult body weight, and they appear on bathroom scales and in medical records in the United Kingdom and Ireland. Produce and freight are never sold by the stone.

The stone is exact by definition at 14 pounds, and the kilogram figure follows from the exact pound. Because results are rounded for display, a stone to kilogram round trip can differ in the last digit.

Reading a stone figure as pounds is the common error: a scale showing 12 stone has measured 168 pounds, not 12. Stones are conventional for body weight, while kilograms serve medical dosing and trade.

Stones sit between pounds and kilograms in size, and mixing them up causes large errors: a stone value is 14 times its pound value and 6.35029318 times its kilogram value. Metric records therefore avoid stones.

An ounce is exactly 28.349523125 grams and one sixteenth of a pound, so sixteen ounces make one pound. That definition makes it the avoirdupois ounce, the unit used for ordinary trade.

Ounces appear on postal and courier weight bands, on food packaging and recipe cards, and in the jewellery trade, though precious metals are quoted in the troy ounce.

The gram and kilogram factors are exact decimal relations, and the imperial factors are exact by definition. Display rounding can still change the last digit on a round trip.

The usual error is confusing the troy ounce with the avoirdupois ounce: the troy ounce is 31.1035 grams, while the avoirdupois ounce is 28.349523125 grams. Ounces suit small parcels and portions, not bulk freight.

Ounces are most often confused with grams in recipes and postal weights, because the factor is 28.349523125 rather than a simple power of ten. Precious metals are quoted in the troy ounce, which is not the same as this ounce.